djangoアプリケーションのherokuでのデプロイがうまくいきません

DjangoアプリケーションをHerokuでデプロイしたいです

djangoで簡単なアプリケーションを作ってherokuでデプロイをしようとしているのですが、最後のgit push heroku masterで下記のエラーが出てしまいます。

発生している問題・エラーメッセージ

Counting objects: 20, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (17/17), done.
Writing objects: 100% (20/20), 4.39 KiB | 224.00 KiB/s, done.
Total 20 (delta 0), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Python app detected
remote:  !     The latest version of Python 3 is python-3.6.5 (you are using python-3.5.2, which is unsupported).
remote:  !     We recommend upgrading by specifying the latest version (python-3.6.5).
remote:        Learn More: https://devcenter.heroku.com/articles/python-runtimes
remote: -----> Installing python-3.5.2
remote: -----> Installing pip
remote: -----> Installing requirements with pip
remote:        Collecting dj-database-url==0.5.0 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 1))
remote:          Downloading https://files.pythonhosted.org/packages/d4/a6/4b8578c1848690d0c307c7c0596af2077536c9ef2a04d42b00fabaa7e49d/dj_database_url-0.5.0-py2.py3-none-any.whl
remote:        Collecting Django==2.0.5 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 2))
remote:          Downloading https://files.pythonhosted.org/packages/23/91/2245462e57798e9251de87c88b2b8f996d10ddcb68206a8a020561ef7bd3/Django-2.0.5-py3-none-any.whl (7.1MB)
remote:        Collecting gunicorn==19.8.1 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 3))
remote:          Downloading https://files.pythonhosted.org/packages/55/cb/09fe80bddf30be86abfc06ccb1154f97d6c64bb87111de066a5fc9ccb937/gunicorn-19.8.1-py2.py3-none-any.whl (112kB)
remote:        Collecting pytz==2018.4 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 4))
remote:          Downloading https://files.pythonhosted.org/packages/dc/83/15f7833b70d3e067ca91467ca245bae0f6fe56ddc7451aa0dc5606b120f2/pytz-2018.4-py2.py3-none-any.whl (510kB)
remote:        Collecting whitenoise==3.3.1 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 5))
remote:          Downloading https://files.pythonhosted.org/packages/0c/58/0f309a821b9161d0e3a73336a187d1541c2127aff7fdf3bf7293f9979d1d/whitenoise-3.3.1-py2.py3-none-any.whl
remote:        Collecting psycopg2==2.5.4 (from -r /tmp/build_4a1440fcd1b08aedec414af6ff73b440/requirements.txt (line 6))
remote:          Downloading https://files.pythonhosted.org/packages/63/c3/802668cb3cfc2880c2a8364623e7105a0257724a2612bb66ec733aaddb8c/psycopg2-2.5.4.tar.gz (682kB)
remote:            Complete output from command python setup.py egg_info:
remote:            running egg_info
remote:            creating pip-egg-info/psycopg2.egg-info
remote:            writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
remote:            writing pip-egg-info/psycopg2.egg-info/PKG-INFO
remote:            writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
remote:            writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
remote:            Error: could not determine PostgreSQL version from '10.4'
remote:
remote:            ----------------------------------------
remote:        Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-q17faica/psycopg2/
remote:  !     Push rejected, failed to compile Python app.
remote:
remote:  !     Push failed
remote: Verifying deploy...
remote:
remote: !       Push rejected to MYBLOGNAME.
remote:
To https://git.heroku.com/MYBLOGNAME.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/MYBLOGNAME.git'

現状

virtualenvの環境下でpython -Vコマンドを打つと、
Python 3.6.5 :: Anaconda custom (64-bit)
と出ます。runtime.txtには
python-3.6.5
と書いてあります。
そもそもPython3.5系をPCにインストールした記憶がないのですが、どういった問題が考えられますでしょうか？
他にも必要な情報がございましたら教えてください。
よろしくお願いします。